1. Technical Field
The present invention relates to memory devices in general, and in particular to an analog access circuit for validating chalcogenide memory cells.
2. Description of Related Art
Chalcogenide random access memory utilizes a thermally activated, rapid, reversible change in the structure of the chalcogenide alloy for storing data. This type of phase-change memories has been under development for several years at semiconductor manufacturing facilities worldwide. A memory cell made of chalcogenide alloy can be programmed to an amorphous state having a high resistance or a polycrystalline state having a low resistance, which can be referred to as a logical “0” or a logical “1,” respectively.
In a chalcogenide memory device, a read failure may come from either a defected chalcogenide memory cell or a defected sense amplifier circuit. It is impossible to differentiate the source of such read failure with digital circuits designed for conventional memory devices.